2013 * XXIV * 1

SISUKORD

http://agrt.emu.ee/pdf/2013_1_sisukord.pdf

TEADUSTÖÖD

Kaldmäe, H., Kass, M., Leming, R., Ots, M.

Kuumtöötlemise mõju rapsikoogi proteiini kvaliteedile

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Effect of heat treatment on rapeseed cake protein quality.Kaldmäe, H., Kass, M., Leming, R., Ots, M. Cold-pressed rapeseed cake are poor sources of ruminal undegraded protein (RUP), protein effective degradability were 85–89%. Heat treatment is one of the most common method use to reduce ruminal protein degradation. Changes of treatment temperature had the greatest effect on the solubility and ruminal degradability of rapeseed cake protein. The higher treatment temperature of the seeds resulted in lower and slower ruminal degradabilty of rapeseed cake protein. The results of defferent study show that heating temperature and duration of heating were both important in protecting rapeseed protein for ruminal degradation. It was concluded from that studies that heating rapeseed 100 °C for 20 min in the present case conditions is a viable method to reduce ruminal degradability of rapeseed cake protein without compromising the intestinal digestibility of RUP.Keywords: rapeseed cake, heat treatment, protein degradation Source: Agraarteadus 2013 (24) 1:3-6

The selenium status of dairy cows in Estonia.Ling, K., Ilves, A., Jaakson, H., Olt, A., Ots, M. Based on earlier soil, forage and animal studies, Estonia is considered a Se-deficient country where Se supplementation of dairy cows has been routine practice for more than 10 years. To evaluate the current Se status of Estonian dairy cows, bulk tank milk samples (n = 218) from farms (n = 110) producing over 60% of the milk purchased in the counties of Estonia, were analysed for the Se concentration. Milk Se content ranged from 5 – 34 μg/kg. The mean Se content of all the samples was 16 μg/kg, indicating dairy cows’ Se status was from high-marginal to adequate depending on the reference level used. The results of the study provide evidence that the Se status of dairy cattle in Estonia has improved. Although Se status was satisfactory on 99 farms (90.8%) there were 10 farms (9.2%) with a milk Se concentration of less than or equal to 10 μg/kg where attention should be given to Se supplementation of the animals.Key-words: bulk milk, trace elements, silage, nutrient deficiency Source: Agraarteadus 2013 (24) 1:15-20

Ground heat pump booster sp function-technical indices and rooms indoor climate.Pomerants, T., Viljasoo, V., Reinvee, M. The object of the study was heating pump Booster SP and indoor climate provided by floor and ventilation heating. The test site, laboratory of ‘Heating pumps and indoor climate’, was in The Estonian University of Life Sciences Institute of Technology. Heating pump together with ventilation system were set to automatically ensure proper indoor climate. The particularities of the laboratory setting are the alternative depth of the ground collector (1.5 m) and two indoor heating contours with different layouts. The operating parameters of heating pump were measured by thermocouple probes which were placed on the nodes of heating pump. Indoor climate, provided by heating pump Booster SP and ventilation system, was assessed with a diagnostics device which sensors were placed 1.5 m from the floor. The operating state of ground contour, two indoor heating contours, heating pump and indoor climate was diagnosed by simultaneous data accusation. Based on data processing the operating state and efficiency of heating pump, indoor climate’s compliance with laws and legislations was assessed Keywords: ground heating pump, thermal-technical parameters, effective state, indoor climate Source: Agraarteadus 2013 (24) 1:21-28

About Jõgeva, Kuusiku and Olustvere soils.Rannik, K., Kõlli, R. In present work the composition and properties of three experimental areas’ (Jõgeva – JKA, Kuusiku – KKA and Olustvere – OKA) soil covers were analyzed in concordance with soil forming (pedo-ecological) conditions and land management practice. The soil cover of JKA is relatively homogenous, whereas its dominant soil species are eluviated (KI) and leached (Ko) brown soils (altogether 83%) and the dominant soil texture of humus cover (topsoil) is slightly pebble loam (90%), as for the rest of JKA the texture is sandy loam. From the 8 associated soil species, the most distributed are gleyed eluviated (KIg) brown soils (~10%). The differences in soil cover composition between three separately studied arable land massifs of JKA were not significant. The soil cover of KKA experimental area is much more heterogeneous, as the contrast by soil genesis was 5 stages and by soil moisture conditions 4 stages. The soil texture of KKA is also approximately two to three times more heterogeneous than others (JKA and OKA,) as in its humus cover the loamy sands (38%), sands (33%) and loams (29%) were found. The character soil species of the KKA are leached gley soils (Go), Ko, KIg and pebble rendzina (K), which form together ~75% from total area and therefore may be classified as dominant soils. With them 10 soil species with variable pedogenetic properties are associated. For receiving suitable areas for experimental fields, the KKA total area was divided into separate (by soil cover more homogeneous, but different from each other by dominant soil species) three arable land massifs: (I) with dominating Ko, K and strongly skeletal pebble rendzina (Kr), (II) where the Kr and K are dominants and (III) with dominating drained Go and KIg. In the soil cover of OKA, the dominant soil species is pseudopodzolic soil (LP, 86%) and dominant humus cover texture is sandy loam (76%), whereas the stage of heterogeneity is very similar to JKA. If JKA is by soil cover composition and properties representative to central Estonian pedo-ecological conditions, then OKA to South Estonian and KKA to North Estonian pedo-ecological conditions. In the work by three research areas (JKA, KKA, OKA) and by their seven arable land massifs, besides the soil cover composition and pedo-ecological conditions, the soil cover pedodiversity, contrast of presented in soil cover soils, humus cover types and agrochemical status are analyzed. From the aspect of dominant soils, the fabric of soil profile and characteristic on soil humus status (humus concentration, thickness and humus stocks of A-horizons) are also treated. Soils of JKA have high environmental protection value due to neutral or slightly acid reaction, optimal humus content, great cation exchange capacity, sufficient solum thickness and good properties of subsoil. The environmental protection ability of KKA soil cover is decreased due to high content of rock fragments in soil and low biological activity of epipedons. In case of OKA, the low environmental protection value results from sandy topsoil texture, acidic soil reaction, and low humus content and stock.Keywords: contrast of soils, environment protective value, humus cover types, humus status, pedodiversity, soil cover composition, soils suitability for crops Source: Agraarteadus 2013 (24) 1:19-37

Possibilities for balancing wind generators’ output power.Toom, K., Peets, T., Annuk, A. Wind is, compared to solar irradiation, a highly stochastic energy source; therefore forecasting wind generator output power is complicated. The aim of this study was how to better fit wind generators (their output power) into energy systems. We studied two options: cutting off wind parks output power chart peaks and combining wind generators with PV panels and batteries. The first way to reach to aim of this study was to analyse different wind park data for finding methods to correct forecast error of output power. Pakri and Aulepa wind parks were chosen. Pakri wind park is located in the best wind conditions in Estonia and Aulepa wind park is located in an average site in a coastal area.The second way to reach to aim of this study was increasing the proportion of renewable fraction, thereby reducing the need of obtaining electrical power from the grid, at different deviations of the unit consumer’s graph, but at the same time the average consumption of the year stays the same. The other important variable in the calculations is the battery size. The solar irradiation data was acquired from Estonian Meteorological and Hydrological Institute (EMHI) Tõravere database and wind data from Tiirikoja database.Keywords: wind generator`s output power, balancing, forecast error, renewable fraction, solar irradiation, batterySource: Agraarteadus 2013 (24) 1:38-46